Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of bette...Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically展开更多
Exploring the nonlinear relationship between air pollution and precursor emissions in Qingdao,eastern China is crucial for improving air quality.We simulated 32 emission reduction scenarios based on different volatile...Exploring the nonlinear relationship between air pollution and precursor emissions in Qingdao,eastern China is crucial for improving air quality.We simulated 32 emission reduction scenarios based on different volatile organic compound(VOC)and nitrogen oxide(NO_(x))emission reduction ratios using the Weather Research and Forecasting-Comprehensive Air Quality Model Extensions model.The emission reduction of VOCs was beneficial for reducing fine particulate matter(PM_(2.5))concentration in January and ozone(O_(3))concentration in June.However,NO_(x)must be reduced by at least 48%and 70%to decrease PM_(2.5)and O_(3)concentrations,respectively,when VOCs are not reduced.The responses of PM_(2.5)and O_(3)concentrations to emission reductions from different sources were also evaluated.The reduction in VOC emissions from different sources decreased the PM_(2.5)concentration in January,and O_(3)concertation in June,while NO_(x)reduction resulted in an increase.Controlling VOC emissions from industry has a positive effect on improving local PM_(2.5)and O_(3),while the emission reductions of NO_(x)from transportation and industry are not conducive to reducing PM_(2.5)and O_(3)concentrations.The synergistic emission reduction pathways for NO_(x)and VOCs during PM_(2.5)and O_(3)combined pollution were also analyzed.The VOC and NO_(x)emission reductions were beneficial for reducing the comprehensive Air Quality Index(sAQI)values.When the NO_(x)emission reduction was large,the sAQI improvement gradually exceeded that of VOCs.A collaborative optimization path should be adopted that focuses on controlling VOCs first,and further control of combined pollution should depend on the deep reduction of NO_(x).展开更多
From the macroscopic viewpoint for describing the acceleration behaviour of drivers, a weighted probabilistic cellular automaton model （the WP model, for short） is proposed by introducing a kind of random accelerati...From the macroscopic viewpoint for describing the acceleration behaviour of drivers, a weighted probabilistic cellular automaton model （the WP model, for short） is proposed by introducing a kind of random acceleration probabilistic distribution function. The fundamental diagrams, the spatiotemporal patterns, are analysed in detail. It is shown that the presented model leads to the results consistent with the empiricaZ data rather well, nonlinear flow-density relationship existing in lower density regions, and a new kind of traific phenomenon called neo-synchronized flow. Furthermore, we give the criterion for distinguishing the high-speed and low-speed neo-synchronized flows and clarify the mechanism of this kind of traffic phenomenon. In addition, the result that the time evolution of distribution of headways is displayed as a normal distribution further validates the reasonability of the neo-synchronized flow. These findings suggest that the diversity and the randomicity of drivers and vehicles have indeed a remarkable effect on traffic dynamics.展开更多
BP neural networks is used to mid-term earthquake prediction in this paper. Some usual prediction parameters of seismology are used as the import units of neural networks. And the export units of neural networks is ca...BP neural networks is used to mid-term earthquake prediction in this paper. Some usual prediction parameters of seismology are used as the import units of neural networks. And the export units of neural networks is called as the character parameter W_0 describing enhancement of seismicity. We applied this method to space scanning of North China. The result shows that the mid-term anomalous zone of W_0-value usually appeared obviously around the future epicenter 1~3 years before earthquake. It is effective to mid-term prediction.展开更多
This study investigates how green innovation drives rural revitalization in China’s sustainable development framework,focusing on institutional thresholds and spatial heterogeneity.We use panel data from 21 prefectur...This study investigates how green innovation drives rural revitalization in China’s sustainable development framework,focusing on institutional thresholds and spatial heterogeneity.We use panel data from 21 prefecture-level cities in Guangdong Province from 2009 to 2022 and apply a threshold regression model to examine both linear and nonlinear effects of green innovation.The results reveal that green innovation positively influences rural revitalization only after surpassing a critical level of regional innovation capacity.This critical threshold effect indicates that the benefits of green innovation for rural development are unevenly distributed and rely heavily on local absorptive capacity and institutional context.Our findings contribute to sustainability research,highlighting how green innovation interacts with policy-driven rural development goals,particularly in emerging economies.Furthermore,this research provides region-specific policy recommendations to support inclusive,innovation-driven,and environmentally sustainable revitalization strategies.This paper integrates institutional and sustainable development theory to provide a deeper understanding of the dynamic role of technological change in reshaping rural development pathways within the global green transition agenda.展开更多
As climatic changes and human uses intensify,resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points,or dramatic shifts in structure and function that are ...As climatic changes and human uses intensify,resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points,or dramatic shifts in structure and function that are often costly and hard to reverse.Evidence indicates that explicitly addressing tipping points leads to improved management outcomes.Drawing on theory and examples from marine systems,we distill a set of seven principles to guide effective management in ecosystems with tipping points,derived from the best available science.These principles are based on observations that tipping points(1)are possible everywhere,(2)are associated with intense and/or multifaceted human use,(3)may be preceded by changes in earlywarning indicators,(4)may redistribute benefits among stakeholders,(5)affect the relative costs of action and inaction,(6)suggest biologically informed management targets,and(7)often require an adaptive response to monitoring.We suggest that early action to preserve system resilience is likely more practical,affordable,and effective than late action to halt or reverse a tipping point.We articulate a conceptual approach to management focused on linking management targets to thresholds,tracking early-warning signals of ecosystem instability,and stepping up investment in monitoring and mitigation as the likelihood of dramatic ecosystem change increases.This approach can simplify and economize management by allowing decision makers to capitalize on the increasing value of precise information about threshold relationships when a system is closer to tipping or by ensuring that restoration effort is sufficient to tip a system into the desired regime.展开更多
Future space missions demand operations on large flexible structures,for example,space webs,the lightweight cable nets deployable in space,which can serve as platforms for very large structures or be used to capture o...Future space missions demand operations on large flexible structures,for example,space webs,the lightweight cable nets deployable in space,which can serve as platforms for very large structures or be used to capture orbital objects.The interest in research on space webs is likely to increase in the future with the development of promising applications such as Furoshiki sat-ellite of JAXA,Robotic Geostationary Orbit Restorer (ROGER) of ESA and Grapple,Retrieve And Secure Payload (GRASP) of NASA.Unlike high-tensioned nets in civil engineering,space webs may be low-tensioned or tensionless,and extremely flexible,owing to the microgravity in the orbit and the lack of support components,which may cause computational difficulties.Mathematical models are necessary in the analysis of space webs,especially in the conceptual design and evaluation for prototypes.A full three-dimensional finite element (FE) model was developed in this work.Trivial truss elements were adopted to reduce the computational complexity.Considering cable is a compression-free material and its tensile stiffness is also variable,we introduced the cable material constitutive relationship to work out an accurate and feasible model for prototype analysis and design.In the static analysis,the stress distribution and global deformation of the webs were discussed to get access to the knowledge of strength of webs with different types of meshes.In the dynamic analysis,special attention was paid to the impact problem.The max stress and global deformation were investigated.The simulation results indicate the interesting phenomenon which may be worth further research.展开更多
The analysis of the relationship between sea ice in Arctic and Antarctic, and the Southern Oscillation Index (SOI) variation on the temporal scale of month, season and year is made in this paper. The negative correlat...The analysis of the relationship between sea ice in Arctic and Antarctic, and the Southern Oscillation Index (SOI) variation on the temporal scale of month, season and year is made in this paper. The negative correlation between sea ice in Arctic and the SOI. and the positive correlation between sea ice in Antarctic and the SOI are found. The variation of sea ice in Antarctic Pacific seems to play an important role in the influence to atmosphere. Their nonlinear relationships present more strongly than the linear relationship between them. The relationship between sea ice in Arctic and Antarctic and the SOI in the early stage is investigated. Their variation shows periodic phenomena. The maximum correlation is used to build the model for forecasting the variation of the SOI on the condition of the sea ice in Arctic and Antarctic. The explained variance of the simulated series is greater than 0.90. There exists a 17-month period in the relationship between sea ice in Arctic and Antarctic and SOI. The existing of the common factor with larger scale is discussed in this paper.展开更多
We develop a statistical framework to use the data of night-time-lights(DN)from satellite to augment official GDP measures,and a non-linear substitution relationship between DN and GDP is given.In this paper,we take a...We develop a statistical framework to use the data of night-time-lights(DN)from satellite to augment official GDP measures,and a non-linear substitution relationship between DN and GDP is given.In this paper,we take advantage of DN instead of GDP to measure the imbalance of regional development(IRD)in China by using the method of bi-dimensional decomposition under the population-weighted coefficient of variation.The method enables us to analyze the contributions of DN components to within-region and between-regions inequality under the framework which has been proposed,we can get the conclusion that the imbalance between-regions rather than within-region is the main reason for the influence of IRD for the whole country in China.展开更多
Exploring the mechanisms between the built environment and active travel is crucial for promoting green transportation and fostering the sustainable development of cities.Existing literature focuses on the correlation...Exploring the mechanisms between the built environment and active travel is crucial for promoting green transportation and fostering the sustainable development of cities.Existing literature focuses on the correlation between the built environment and active travel in urban centers,with limited studies on suburban environments,ignoring the implications of spatial heterogeneity.This study conducts a comprehensive spatio-temporal analysis of the active travel behavior of suburban residents,and investigates the nonlinear relationship between the suburban built environment and active travel.A novel hybrid modeling framework that combines extreme gradient boosting(XGBoost)and multi-scale geographic weighted regression(MGWR)is introduced to forecast suburban active travel demand with the consideration of the nonlinearity and spatial heterogeneity in parameter estimates.Shapley additive explanation(SHAP)is used to elucidate the non-linear relationship between built environment variables and active travel.The results indicate that the proposed hybrid model performs the best with high predictive power and interpretability.The density of tourist attractions,transportation facilities,and household properties emerge as the three most influential factors affecting residents’active travel behavior.Social-economic attributes contribute 15.70%to the prediction,while three categories of built environment variables(accessibility,transportation facilities,and land use)contribute 7.31%,5.13%,and 71.87%,respectively.The hybrid model appears to be effective in identifying the nonlinear relationship and threshold effects between built environment variables and active travel.Besides,the model provides actionable insights into designing sustainable and efficient suburban environments,supporting targeted planning and policy-making efforts.展开更多
基金supported by The HongKong Polytechnic University Research Grants(No.1-BB81)grants from National Natural Science Foundation of China,Nos.10872078 and 10832012
文摘Precisely quantifying the strength of the proximal femur and accurately assessing hip fracture risk would enable those at high risk to be identified so that preventive interventions could be taken.Development of better measures of femoral strength using the clinically
基金funded by the Shandong Postdoctoral Science Foundation(No.SDCX-ZG-202303008).
文摘Exploring the nonlinear relationship between air pollution and precursor emissions in Qingdao,eastern China is crucial for improving air quality.We simulated 32 emission reduction scenarios based on different volatile organic compound(VOC)and nitrogen oxide(NO_(x))emission reduction ratios using the Weather Research and Forecasting-Comprehensive Air Quality Model Extensions model.The emission reduction of VOCs was beneficial for reducing fine particulate matter(PM_(2.5))concentration in January and ozone(O_(3))concentration in June.However,NO_(x)must be reduced by at least 48%and 70%to decrease PM_(2.5)and O_(3)concentrations,respectively,when VOCs are not reduced.The responses of PM_(2.5)and O_(3)concentrations to emission reductions from different sources were also evaluated.The reduction in VOC emissions from different sources decreased the PM_(2.5)concentration in January,and O_(3)concertation in June,while NO_(x)reduction resulted in an increase.Controlling VOC emissions from industry has a positive effect on improving local PM_(2.5)and O_(3),while the emission reductions of NO_(x)from transportation and industry are not conducive to reducing PM_(2.5)and O_(3)concentrations.The synergistic emission reduction pathways for NO_(x)and VOCs during PM_(2.5)and O_(3)combined pollution were also analyzed.The VOC and NO_(x)emission reductions were beneficial for reducing the comprehensive Air Quality Index(sAQI)values.When the NO_(x)emission reduction was large,the sAQI improvement gradually exceeded that of VOCs.A collaborative optimization path should be adopted that focuses on controlling VOCs first,and further control of combined pollution should depend on the deep reduction of NO_(x).
基金supported by the National Basic Research Program of China (Grant No 2006CB705500)the National Natural Science Foundation of China (Grant Nos 10532060 and 10562001)+1 种基金the Special Research Fund for the Doctoral Program in Higher Education of China (Grant No SRFDP 20040280014)the Shanghai Leading Academic Discipline Project of China (Grant NoY0103)
文摘From the macroscopic viewpoint for describing the acceleration behaviour of drivers, a weighted probabilistic cellular automaton model （the WP model, for short） is proposed by introducing a kind of random acceleration probabilistic distribution function. The fundamental diagrams, the spatiotemporal patterns, are analysed in detail. It is shown that the presented model leads to the results consistent with the empiricaZ data rather well, nonlinear flow-density relationship existing in lower density regions, and a new kind of traific phenomenon called neo-synchronized flow. Furthermore, we give the criterion for distinguishing the high-speed and low-speed neo-synchronized flows and clarify the mechanism of this kind of traffic phenomenon. In addition, the result that the time evolution of distribution of headways is displayed as a normal distribution further validates the reasonability of the neo-synchronized flow. These findings suggest that the diversity and the randomicity of drivers and vehicles have indeed a remarkable effect on traffic dynamics.
文摘BP neural networks is used to mid-term earthquake prediction in this paper. Some usual prediction parameters of seismology are used as the import units of neural networks. And the export units of neural networks is called as the character parameter W_0 describing enhancement of seismicity. We applied this method to space scanning of North China. The result shows that the mid-term anomalous zone of W_0-value usually appeared obviously around the future epicenter 1~3 years before earthquake. It is effective to mid-term prediction.
文摘This study investigates how green innovation drives rural revitalization in China’s sustainable development framework,focusing on institutional thresholds and spatial heterogeneity.We use panel data from 21 prefecture-level cities in Guangdong Province from 2009 to 2022 and apply a threshold regression model to examine both linear and nonlinear effects of green innovation.The results reveal that green innovation positively influences rural revitalization only after surpassing a critical level of regional innovation capacity.This critical threshold effect indicates that the benefits of green innovation for rural development are unevenly distributed and rely heavily on local absorptive capacity and institutional context.Our findings contribute to sustainability research,highlighting how green innovation interacts with policy-driven rural development goals,particularly in emerging economies.Furthermore,this research provides region-specific policy recommendations to support inclusive,innovation-driven,and environmentally sustainable revitalization strategies.This paper integrates institutional and sustainable development theory to provide a deeper understanding of the dynamic role of technological change in reshaping rural development pathways within the global green transition agenda.
基金Primary funding was provided by the Gordon and Betty Moore Foundation,with additional support to K.A.Selkoe from National Science Founda-tion(BioOCE Award 1260169).
文摘As climatic changes and human uses intensify,resource managers and other decision makers are taking actions to either avoid or respond to ecosystem tipping points,or dramatic shifts in structure and function that are often costly and hard to reverse.Evidence indicates that explicitly addressing tipping points leads to improved management outcomes.Drawing on theory and examples from marine systems,we distill a set of seven principles to guide effective management in ecosystems with tipping points,derived from the best available science.These principles are based on observations that tipping points(1)are possible everywhere,(2)are associated with intense and/or multifaceted human use,(3)may be preceded by changes in earlywarning indicators,(4)may redistribute benefits among stakeholders,(5)affect the relative costs of action and inaction,(6)suggest biologically informed management targets,and(7)often require an adaptive response to monitoring.We suggest that early action to preserve system resilience is likely more practical,affordable,and effective than late action to halt or reverse a tipping point.We articulate a conceptual approach to management focused on linking management targets to thresholds,tracking early-warning signals of ecosystem instability,and stepping up investment in monitoring and mitigation as the likelihood of dramatic ecosystem change increases.This approach can simplify and economize management by allowing decision makers to capitalize on the increasing value of precise information about threshold relationships when a system is closer to tipping or by ensuring that restoration effort is sufficient to tip a system into the desired regime.
文摘Future space missions demand operations on large flexible structures,for example,space webs,the lightweight cable nets deployable in space,which can serve as platforms for very large structures or be used to capture orbital objects.The interest in research on space webs is likely to increase in the future with the development of promising applications such as Furoshiki sat-ellite of JAXA,Robotic Geostationary Orbit Restorer (ROGER) of ESA and Grapple,Retrieve And Secure Payload (GRASP) of NASA.Unlike high-tensioned nets in civil engineering,space webs may be low-tensioned or tensionless,and extremely flexible,owing to the microgravity in the orbit and the lack of support components,which may cause computational difficulties.Mathematical models are necessary in the analysis of space webs,especially in the conceptual design and evaluation for prototypes.A full three-dimensional finite element (FE) model was developed in this work.Trivial truss elements were adopted to reduce the computational complexity.Considering cable is a compression-free material and its tensile stiffness is also variable,we introduced the cable material constitutive relationship to work out an accurate and feasible model for prototype analysis and design.In the static analysis,the stress distribution and global deformation of the webs were discussed to get access to the knowledge of strength of webs with different types of meshes.In the dynamic analysis,special attention was paid to the impact problem.The max stress and global deformation were investigated.The simulation results indicate the interesting phenomenon which may be worth further research.
基金This study is supported by the "National Key Program for Developing Basic Science G1998040901-1".
文摘The analysis of the relationship between sea ice in Arctic and Antarctic, and the Southern Oscillation Index (SOI) variation on the temporal scale of month, season and year is made in this paper. The negative correlation between sea ice in Arctic and the SOI. and the positive correlation between sea ice in Antarctic and the SOI are found. The variation of sea ice in Antarctic Pacific seems to play an important role in the influence to atmosphere. Their nonlinear relationships present more strongly than the linear relationship between them. The relationship between sea ice in Arctic and Antarctic and the SOI in the early stage is investigated. Their variation shows periodic phenomena. The maximum correlation is used to build the model for forecasting the variation of the SOI on the condition of the sea ice in Arctic and Antarctic. The explained variance of the simulated series is greater than 0.90. There exists a 17-month period in the relationship between sea ice in Arctic and Antarctic and SOI. The existing of the common factor with larger scale is discussed in this paper.
基金National Social Science Foundation of China(20BTJ027)。
文摘We develop a statistical framework to use the data of night-time-lights(DN)from satellite to augment official GDP measures,and a non-linear substitution relationship between DN and GDP is given.In this paper,we take advantage of DN instead of GDP to measure the imbalance of regional development(IRD)in China by using the method of bi-dimensional decomposition under the population-weighted coefficient of variation.The method enables us to analyze the contributions of DN components to within-region and between-regions inequality under the framework which has been proposed,we can get the conclusion that the imbalance between-regions rather than within-region is the main reason for the influence of IRD for the whole country in China.
基金supported by the National Nature Science Foundation of China(No.52302441)the Science and Technology Commission of Shanghai Municipality(No.22dz1207500).
文摘Exploring the mechanisms between the built environment and active travel is crucial for promoting green transportation and fostering the sustainable development of cities.Existing literature focuses on the correlation between the built environment and active travel in urban centers,with limited studies on suburban environments,ignoring the implications of spatial heterogeneity.This study conducts a comprehensive spatio-temporal analysis of the active travel behavior of suburban residents,and investigates the nonlinear relationship between the suburban built environment and active travel.A novel hybrid modeling framework that combines extreme gradient boosting(XGBoost)and multi-scale geographic weighted regression(MGWR)is introduced to forecast suburban active travel demand with the consideration of the nonlinearity and spatial heterogeneity in parameter estimates.Shapley additive explanation(SHAP)is used to elucidate the non-linear relationship between built environment variables and active travel.The results indicate that the proposed hybrid model performs the best with high predictive power and interpretability.The density of tourist attractions,transportation facilities,and household properties emerge as the three most influential factors affecting residents’active travel behavior.Social-economic attributes contribute 15.70%to the prediction,while three categories of built environment variables(accessibility,transportation facilities,and land use)contribute 7.31%,5.13%,and 71.87%,respectively.The hybrid model appears to be effective in identifying the nonlinear relationship and threshold effects between built environment variables and active travel.Besides,the model provides actionable insights into designing sustainable and efficient suburban environments,supporting targeted planning and policy-making efforts.
